1. Field of the Invention
The present invention relates to a network camera system which distributes video images to a plurality of clients via a network.
2. Description of the Related Art
Recently, there have been proposed many network camera systems which distribute video shot by a digital video camera or the like via a network such as the Internet or a LAN so that a plurality of clients (computer terminals) can monitor it at remote places. Another known technique is a system which allows a client at a remote place not only to simply monitor video image but also to remote-control the pan/tilt angle and zoom ratio of the camera on the remote client side.
In a system capable of distributing remote-controllable video image to a plurality of clients, some ranges that specific clients should not see exist in the camera shootable range. For example, part of video from a camera installed outdoors may invade privacy and infringe the right of portrait.
To solve this problem, a person (to be referred to as a camera administrator hereinafter) who installs a camera controls the camera against specific clients so as to set a view restriction on the camera shootable range. By setting the view restriction, shooting of the view-restricted range is inhibited, the resolution of video within the view-restricted range is decreased, or video having undergone an image process such as mosaicking is distributed (see Japanese Patent Laid-Open Nos. 10-161213, 2001-136514, and 2002-027425).
A conventional system allows only a camera administrator to set a view restriction on the camera shootable range. However, a user whose area exists within the camera shootable range may exist among clients (to be referred to as users or area administrators hereinafter) who monitor video image. For example, when a camera is installed for monitoring in a public place such as a residential district, each user whose area exists within the camera shootable range may want to permit or inhibit shooting in consideration of privacy and security. It is desirable to give a user to be shot a privilege to set a restriction on the shootable range, instead of entrusting a camera administrator with setting of the view restriction.
When the camera administrator manages the view restriction in a conventional manner, it is cumbersome and difficult to distribute a video image which reflects all user requests.